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arXiv 0911.3593astro-ph.CO
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超铝红外半导体的亚毫米波特性

The Submillimetre Properties of Ultraluminous Infrared Galaxies

D. L. Clements, L. Dunne, S. A. Eales

摘要:

我们提出了一个完整的本地ULIRGs样本的SCUBA观测结果。23个源的初始样本中有20个在850 um处被检测到,并且近一半的对象也在450 um处被检测到。这些数据与另外7个ULIRGs的现有观测结果相结合,以产生目前可用的ULIRGs亚毫米观测的最大样本。我们使用类似的技术SLUGS调查,以适应尘埃光谱能量分布(SED),他们的远红外发射。我们发现,ULIRGs有一个更高的尘埃温度比低光度的对象(42 K相比,35 K)和陡峭的发射率指数。对于那些对象,450微米通量是可用的,我们也尝试了两个组件的灰尘SED适合,与温暖和凉爽的灰尘和灰尘的发射率指数β =2。这样的模型已经被发现是一个很好的适合较低的光度系统。我们发现,它也适用于ULIRGs,但ULIRGs有一个较小的冷尘埃成分。比较ULIRG和更正常的旋涡星系的尘埃质量表明,ULIRG的尘埃含量仅仅是合并引发ULIRG活动的两个星系的尘埃含量的总和。我们研究了850微米光度函数的高端,发现结果与早期SLUGS调查的结果一致。我们还发现,ULIRGs只占850 um光度函数高端的50%左右,LIRGs包含大量的冷尘埃可能是负责其余的。

英文摘要:

We present the results of SCUBA observations of a complete sample of local ULIRGs. Twenty of the initial sample of 23 sources are detected at 850 um and nearly half of the objects are also detected at 450 um. This data is combined with existing observations of a further seven ULIRGs to produce the largest sample of submm observations of ULIRGs currently available. We use similar techniques to the SLUGS survey to fit dust spectral energy distributions (SEDs) to their far-IR emission. We find that ULIRGs have a higher dust temperature than lower luminosity objects (42K compared to 35K) and a steeper emissivity index. For those objects where 450 um fluxes are available we also attempt a two component dust SED fit, with warm and cool dust and a dust emissivity index of beta=2. Such a model has been found to be a good fit to lower luminosity systems. We find that it also works well for ULIRGs, but that ULIRGs have a smaller cold dust component. Comparison of the dust mass derived for ULIRGs and more normal spiral galaxies suggests that the dust content of a ULIRG is simply the combined dust content of the two galaxies whose merger has triggered the ULIRG activity. We examine the high end of the 850 um luminosity function and find results consistent with those of the earlier SLUGS survey. We also find that ULIRGs make up only about 50% of the high end of the 850 um luminosity function, with LIRGs containing a large mass of cool dust likely to be responsible for the rest.

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